Myostatin is a key mediator between energy metabolism and endurance capacity of skeletal muscle

Myostatin (Mstn) participates in the regulation of skeletal muscle size and has emerged as a regulator of muscle metabolism. Here, we hypothesized that lack of myostatin profoundly depresses oxidative phosphorylation-dependent muscle function. Toward this end, we explored Mstn/ mice as a model for the constitutive absence of myostatin and AAV-mediated overexpression of myostatin propeptide as a model of myostatin blockade in adult wild-type mice. We show that muscles from Mstn/ mice, although larger and stronger, fatigue extremely rapidly. Myostatin deficiency shifts muscle from aerobic toward anaerobic energy metabolism, as evidenced by decreased mitochondrial respiration, reduced expression of PPAR transcriptional regulators, increased enolase activity, and exercise-induced lactic acidosis. As a consequence, constitutively reduced myostatin signaling diminishes exercise capacity, while the hypermuscular state of Mstn/ mice increases oxygen consumption and the energy cost of running. We wondered whether these results are the mere consequence of the congenital fiber-type switch toward a glycolytic phenotype of constitutive Mstn/ mice. Hence, we overexpressed myostatin propeptide in adult mice, which did not affect fiber-type distribution, while nonetheless causing increased muscle fatigability, diminished exercise capacity, and decreased Pparb/d and Pgc1a expression. In conclusion, our results suggest that myostatin endows skeletal muscle with high oxidative capacity and low fatigability, thus regulating the delicate balance between muscle mass, muscle force, energy metabolism, and endurance capacity.

INCREASED WATER STORAGE CAPACITY IN CACTUS WOOD: A STUDY IN THE TRIBE CEREEAE (CACTOIDEAE, CACTACEAE)

Secondary xylem of fibrous cactus wood is characterized by short narrow vessel elements with both simple perforation plates and large intervessel pits, libriform septate fibers, and large rays. These are present in basal cactus taxa, as well as in many other groups of the family. In Cactoideae, the most diversified and most derived subfamily, there are remarkable variations found in the secondary xylem, with the more highly derived taxa containing the greatest water storage capacity. Unlignified parenchyma is one specialization found in the fibrous wood of cacti. We observed this tissue in the secondary xylem at the base of the sterns of several Brazilian endemic species of Arrojadoa, Melocactus, and Stephanocereus, all members of the tribe Cereeae. In Arrojadoa and Melocactus the unlignified parenchyma occurs in lines and bands amongst the axial and radial xylem elements, while in Stephanocereus it is mainly restricted to the rays and does not form bands. We address the adaptive importance of the unlignified parenchyma in the fibrous wood in tribe Cereeae and the family Cactaceae as a whole.

Using gap-crossing capacity to evaluate functional connectivity of two Atlantic rainforest birds and their response to fragmentation

One of the main consequences of habitat loss and fragmentation is the increase in patch isolation and the consequent decrease in landscape connectivity. In this context, species persistence depends on their responses to this new landscape configuration, particularly on their capacity to move through the interhabitat matrix. Here, we aimed first to determine gap-crossing probabilities related to different gap widths for two forest birds (Thamnophilus caerulescens, Thamnophilidae, and Basileuterus culicivorus, Parulidae) from the Brazilian Atlantic rainforest. These values were defined with a playback technique and then used in analyses based on graph theory to determine functional connections among forest patches. Both species were capable of crossing forest gaps between patches, and these movements were related to gap width. The probability of crossing 40 m gaps was 50% for both species. This probability falls to 10% when the gaps are 60 m (for B. culicivorus) or 80 m (for T caerulescens). Actually, birds responded to stimulation about two times more distant inside forest trials (control) than in gap-crossing trials. Models that included gap-crossing capacity improved the explanatory power of species abundance variation in comparison to strictly structural models based merely on patch area and distance measurements. These results highlighted that even very simple functional connectivity measurements related to gap-crossing capacity can improve the understanding of the effect of habitat fragmentation on bird occurrence and abundance.

The information capacity of hypercycles

Hypercycles are information integration systems which are thought to overcome the information crisis of prebiotic evolution by ensuring the coexistence of several short templates. For imperfect template replication, we derive a simple expression for the maximum number of distinct templates n(m). that can coexist in a hypercycle and show that it is a decreasing function of the length L of the templates. In the case of high replication accuracy we find that the product n(m)L tends to a constant value, limiting thus the information content of the hypercycle. Template coexistence is achieved either as a stationary equilibrium (stable fixed point) or a stable periodic orbit in which the total concentration of functional templates is nonzero. For the hypercycle system studied here we find numerical evidence that the existence of an unstable fixed point is a necessary condition for the presence of periodic orbits. (C) 2008 Elsevier Ltd. All rights reserved.

Saliva flow rate, buffer capacity, and pH of autistic individuals

The objective of the study was to evaluate saliva flow rate, buffer capacity, pH levels, and dental caries experience (DCE) in autistic individuals, comparing the results with a control group (CG). The study was performed on 25 noninstitutionalized autistic boys, divided in two groups. G1 composed of ten children, ages 3-8. G2 composed of 15 adolescents ages 9-13. The CG was composed of 25 healthy boys, randomly selected and also divided in two groups: CG3 composed of 14 children ages 4-8, and CG4 composed of 11 adolescents ages 9-14. Whole saliva was collected under slight suction, and pH and buffer capacity were determined using a digital pHmeter. Buffer capacity was measured by titration using 0.01 N HCl, and the flow rate expressed in ml/min, and the DCE was expressed by decayed, missing, and filled teeth (permanent dentition [DMFT] and primary dentition [dmft]). Data were plotted and submitted to nonparametric (Kruskal-Wallis) and parametric (Student`s t test) statistical tests with a significance level less than 0.05. When comparing G1 and CG3, groups did not differ in flow rate, pH levels, buffer capacity, or DMFT. Groups G2 and CG4 differ significantly in pH (p = 0.007) and pHi = 7.0 (p = 0.001), with lower scores for G2. In autistic individuals aged 3-8 and 9-13, medicated or not, there was no significant statistical difference in flow rate, pH, and buffer capacity. The comparison of DCE among autistic children and CG children with deciduous (dmft) and mixed/permanent decayed, missing, and filled teeth (DMFT) did not show statistical difference (p = 0.743). Data suggest that autistic individuals have neither a higher flow rate nor a better buffer capacity. Similar DCE was observed in both groups studied.

Radical Scavenging Capacity of Piper arboreum and Piper tuberculatum (Piperaceae)

In the scope of our ongoing researchers on antioxidant compounds, twenty four extracts and fractions obtained from Piper arboreum Aublet and Piper tuberculatum Jacq. (Piperaceae) were screened for radical scavenging capacity (RSC) by using DPPH colorimetric assay. The strongest activity was found in ethyl acetate fractions from the leaves of P. arboreum IC(50) = 5.70 mu g/mL) and P. tuberculatum IC(50) = 8.40 mu g/mL). Hydromethanol fractions of the leaves of P. tuberculatum and P. arboreum showed moderate RSC, with values of IC(50) (mu g/mL) of 11.9 and 19.2, respectively. Additionally, a brief phytochemical study of the ethyl acetate fraction of P. arboreum leaves affording quercetin (1) and quercitrin (2), two flavonols with antioxidant activity previously described in the literature.

Antioxidant Capacity and Larvicidal and Antifungal Activities of Essential Oils and Extracts from Piper krukoffii

The leaves and twigs of Piper krukoffii, collected in the Carajas National Forest, north Brazil, yielded essential oils (2.0% and 0.8%), the main constituents of which were myristicin (40.3% and 26.7%), apiole (25.4% and 34.1%) and elemicin (2.8% and 3.0%). The antioxidant activities of the oils, methanol extract and its sub-fractions were evaluated. The DPPH EC(50) values varied from the ethyl acetate sub-fraction (73.4 +/- 3.7 mu g/mL) to the methanol extract (24.9 +/- 0.8 mu g/mL), and the ABTS TEAC values ranged in the same order from 265.7 to 349.2 mu Mol TE/g. These results indicated a significant antioxidant activity for the plant. The lignans (-)-kusunokin, yatein, (-)-hinokin and cubebin were identified in the methanol extract. The hydro-methanolic sub-fraction showed a high value for total phenol content (106.5 +/- 0.7 mg GAE/g), as well as (1)H NMR signals for sugar moieties. Crude extracts and sub-fractions were also able to inhibit beta-carotene bleaching, varying from 22.4 to 47.1%. The oils from the leaves and twigs showed strong larvicidal (21.4 and 3.6 mu g/mL) and fungicide (0.5 and 0.1 mu g/mL) activities.

Sugarcane spirit extracts of oak and Brazilian woods: antioxidant capacity and activity

Sugarcane spirit extracts of six different Brazilian woods for potential use in manufacturing aging casks were compared with similar extracts of five oak samples from different geographic origin and heat treatment regarding: (1) content of phenolics and copper; (2) radical reducing capacity and reactivity toward 2,2-diphenyl-1-picrylhydrazyl radical (DPPH center dot); and (3) effect on the rate of oxygen depletion rate in a peroxidating lipid model system. Total phenolic contents of the Brazilian wood extracts ranged from 0.65 (canela-sassafras) to 6.4 (jatoba) mmol(GAE) L(-1) and from 1.39 to 2.87 mmol(GAE) L(-1) for oak extracts. Flavonoids ranged from 1.54 x 10(-4) (ipe) to 6.5 x 10(-2) (oak) mmol(rutin) L(-1), and tannins from below the detection limit to 0.22 (jatoba) mmol(tannic acid) L(-1). Correlation was observed for the antioxidant capacity versus phenolics/flavonoids/tannins content, where oak extracts exhibit the highest radical scavenging capacity compared to Brazilian woods. Rate constant for radical scavenging by the extracts ranged from 4.9 x 10(3) M(-1) s(-1)(canela-sassafras) to 9.7 x 10(4) M(-1) s(-1) (oak). The oxygen consumption index showed the Brazilian woods amendoim and jatoba to be more efficient inhibitors than the oak extracts for lipid autoxidation initiated by metmyoglobin, despite that the oak extracts seem to be more efficient to scavenge DPPH center dot. No simple correlation with phenolics or copper content could be established, and a prooxidative tendency was observed for the extracts of canela-sassafras, castanheira, and louro-canela.

Electrochemical determination of the antioxidant capacity: The ceric reducing/antioxidant capacity (CRAC) assay

The CRAC assay is a direct electron transfer test of antioxidant capacity for several organic compounds. The ability of eight different compounds in reducing Cc 41 was studied by chronoamperometric measurements of the remaining Ce(3+) species. The following antioxidant classification was observed: tannic acid >> quercetin > rutin > gallic acid approximate to catechin > ascorbic acid > BHA > Trolox. These results agree with others already published and a good correlation (R(2) = 0.937) was found with the classical spectrophotometric FRAP assay. The CRAC assay is simple, fast, free from sample pretreatment and applicable to nontransparent samples.

Does absorptive capacity affect project performance? A study based on project management practices, organization learning, and knowledge

The literature has emphasized that absorptive capacity (AC) leads to performance, but in projects its influences still unclear. Additionally, the project success is not well understood by the literature, and AC can be an important mechanism to explain it. Therefore, the purpose of this study is to investigate the effect of absorptive capacity on project performance in the construction industry of São Paulo State. We study this influence through potential and realized absorptive capacity proposed by Zahra and George (2002). For achieving this goal, we use a combination of qualitative and quantitative research. The qualitative research is based on 15 interviews with project managers in different sectors to understand the main constructs and support the next quantitative phase. The content analysis was the technique used to analyze those interviews. In quantitative phase through a survey questionnaire, we collected 157 responses in the construction sector with project managers. The confirmatory factor analysis and hierarchical linear regression were the techniques used to assess the data. Our findings suggest that the realized absorptive capacity has a positive influence on performance, but potential absorptive capacity and the interactions effect have no influence on performance. Moreover, the planning and monitoring have a positive impact on budget and schedule, and customer satisfaction while risk coping capacity has a positive impact on business success. In academics terms, this research enables a better understanding of the importance of absorptive capacity in the construction industry and it confirms that knowledge application in processes and routines enhances performance. For management, the absorptive capacity enables the improvements of internal capabilities reflected in the increased project management efficiency. Indeed, when a company manages project practices efficiently it enhances business and project performance; however, it needs initially to improve its internal abilities to enrich processes and routines through relevant knowledge.

Contribution to the chemoreception capacity of juvenile Loggerhead sea turtles (Caretta caretta, L.)

Loggerhead sea turtle juveniles (Caretta caretta), pelagic stage, are found in waters of Madeira archipelago. Pelagic turtles are in the main growth phase of their life cycle and consequently higher energy needs. However, knowledge about the ecology of pelagic loggerhead sea turtles is still quite rudimentary, mainly about the mechanisms that lead them to find food in the vast ocean. Studies with other pelagic species, such as procellariiform birds, revealed that the olfactory system play an important role for the detection of feeding areas, through the detection of concentration peaks of DMS (dimethylsulfide), a scent compound that naturally exists in the marine environment and it is related to areas of high productivity. Based on the assumption that loggerhead sea turtles use a similar mechanism, behavioural experiments were conducted in order to analyze the chemoreception capacity to DMS (airborne chemoreception - theoretically responsible for the long distance detection of areas with food patches; and aquatic chemoreception - theoretically responsible for the short distance detection of preys). The first step was to observe if pelagic loggerheads demonstrate sensitivity to DMS and the second was to verify if they really use the DMS, in natural conditions, as an airborne cue to find areas where food patches might be available. Four juveniles of loggerhead sea turtles were tested in captivity and three wild turtles in the open ocean. The results of airborne chemoreception experiments in captivity revealed that one turtle clearly demonstrated sensitivity to DMS and the sea experiments confirmed this result. However, the experiments were not conclusive on the question whether the pelagic turtles actually use the DMS as an airborne cue to detect long distance food patches. In aquatic chemoreception experiments was not observed sensitivity to DMS by the three sea turtles tested. In the classical conditioning experiment, where DMS and food were given nearly at the same time revealed that after a certain period of time, the sea turtle tested did not associated the DMS stimulus with a possible food reward. The main cause of mortality of loggerhead sea turtles in Madeira waters is due to the accidental capture (bycatch) by deep pelagic longlines fishery which the target species is the black-scabbard (Aphanopus carbo) fish. Chub mackerel (Scomber japonicus) is one of the baits used in this fishery. Aquatic chemoreception experiments were conducted in order to evaluate the attractiveness of the chub mackerel for sea turtles. For the three sea turtles tested, the results showed that in 90% of the cases the sea turtles were extremely attracted by the underwater smell of this fish.

Relationship between antioxidant capacity and total phenolic content of red, rosé and white wines

Phenolic compounds are one of the most important quality parameters of wines, since they contribute to wine organoleptic characteristics such as colour, astringency, and bitterness. Furthermore, several studies have pointed out that many show biological properties of interest, related to their antioxidant capacity. This antioxidant activity has been thoroughly studied and a wide variety of methods have been developed to evaluate it. In this study, the antioxidant activity of commercial Terras Madeirenses Portuguese wines (Madeira Island) was measured by three different analytical methods: [1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTSradical dot+)) radical cation decolourisation, and ferric reducing/antioxidant power (FRAP) for the evaluation of reducing power (PR) and correlate them with the total phenolic content determined with the Folin–Ciocalteu’s reagent using gallic acid as a standard. The total polyphenol concentration was found to vary from 252 to 1936 mg/l gallic acid equivalents (GAE). The antiradical activity varied from 0.042 to 0.715 mM Trolox equivalents and the antioxidant capacity varied from 344 to 1105 mg/l gallic acid equivalents (GAE). For the reduction power we obtained 3.45–3.86 mM quercetin equivalents.

Biological aspects and predatory capacity of Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) fed on Alabama argillacea (Hübner) (Lepidoptera: Noctuidae) reared on cotton genotypes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Meiotic inhibition of bovine oocytes in medium supplemented with a serum replacer and hormones: effects on meiosis progression and developmental capacity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of heat exposure on the thermoregulatory responses of selected naked neck chickens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)